In today's modern vehicles, the exhaust manifolds of internal combustion engines can reach under-the-hood temperatures in the neighborhood of 1600 degrees Fahrenheit. Such high temperatures can create significant risks of damage to components, such as electronic components, nested under the hood. Thus, protection is warranted, and has been provided via use of heat shields designed to cover up, or partially block, and hence to insulate, exhaust manifolds and other heat generating components.
Manifold heat shields conventionally mount to the exhaust manifold of an internal combustion engine with a stand-off bracket or mounting boss. The heat shields are secured to the manifold by at least one bolt that extends through the heat shield and into the mounting boss or the stand-off bracket. Typically, the heat shield is connected to the manifold in more than one location.
It can be appreciated that where the heat shield is connected to the exhaust manifold, the temperature in the heat shield can be at its greatest due to heat conducting from the manifold directly into the heat shield. Thus, the connection points between the heat shield and the exhaust manifold must be able to withstand severe temperature conditions.
In most cases, the heat shield and the manifold are not constructed of the same material. Thus, the manifold expands and contracts differently than the heat shield in response to heat or the lack thereof. The different relative movement of the manifold and heat shield can make alignment of the two difficult. It would therefore be preferable to provide a solution in a heat shield that accommodates these differences.
Typically, the entire heat shield is constructed of a material designed to withstand the conditions at the connection point with the manifold. However, the rest of the heat shield may not be exposed to such severe conditions. Thus, it would be advantageous to develop a mounting configuration that effectively insulated the mounting areas of the heat shield from the rest of the shield so that the majority of the shield could be constructed of a lower cost or lower melting point, low mass material.
In addition, it would be advantageous to develop a mounting configuration that simultaneously functioned as an isolator for mechanical vibration from the engine. It would be further advantageous to be able to tune an isolator for a particular application to minimize transmission of any vibrations.